Method of fabricating thermoplastic yarn



p 1957 E. P. MERSEREAU, JR

METHOD OF FABRICATING THERMOPLASTIC YARN Filed Oct. 25, 1954 INVENTQR. V5/10 Y /75c/e54z/, fe

A fro/way United States Patent METHOD OF FABRICATING THERMOPLASTIC YARNEmory P. Mersereau, Jr., Thornwood, N. Y., assignor to MohascoIndustries, Inc., a corporation of New York Application October 25,1954, Serial No. 464,615

7 Claims. (Cl. 2872) This invention relates to a method of making afabric from yarn composed of synthetic thermoplastic materials and hasfor an object to produce a fabric having novel and improvedcharacteristics.

Another object is to produce a woven pile fabric of the above type inwhich the pile is cockled or coiled.

Another object is to provide a method for temporarily setting a cockledor coiled synthetic thermoplastic yarn in straight condition forweaving.

Another object is to provide a method for treating such a yarn to causethe yarn to assume a permanent cockled or coiled form after having beenwoven while in a temporarily straight form.

Other objects and advantages will be apparent as the nature of theinvention is more fully disclosed.

U. S. Patent No. 2,662,558 describes a method of making a coiled piletuft which involves giving a hard ply twist to a yarn composed of two ormore plies, permanently setting the ply twist, then twisting the yarn inthe reverse direction a sufiicient number of turns to pass the Zerotwist point and impart a loose twist in the reverse direction, andtemporarily setting the reverse twisted yarn while held under sufiicienttension to maintain the yarn straight. The straight set yarn is thenwoven as pile in a pile fabric in an Axminster loom after which thetemporary straight set is removed, whereupon the yarn coils upon itselfwith the plies separated to form interleaved helices due to the internalstrains produced by the reverse twist.

When synthetic thermoplastic yarns are used, such as nylon, Orlon,Dacron, Acrilan, saran or the like which have well defined memorycharacteristics, they may be permanently set in the hard twisted, pliedcondition by suitable heat treatment to bring the yarns to the plasticcondition required to remove the internal strains which give rise to thememory characteristic. However, such yarns, after reverse twistingcannot be temporarily set by heat alone since the heat would beineffective until the above plastic conditions are reached and thiswould produce a permanent set in the reverse twisted form instead of thetemporary set which is desired. Since such yarns are hydrophobic theaddition of moisture likewise is ineffective.

In accordance with this invention the thermoplastic yarn is settemporarily in straight form by first pulling the yarn straight, thencoating the yarn with a soluble sizing which is capable of forming aprotective coating on the yarn of sutficient stiffness to overcome thephysical forces which tend to cause the yarn to cockle or coil and iscapable of holding the yarn in straight, but flexible form suitable forweaving. The effect continues until the coating is removed by washing ordissolving the coating after which the yarn is free to assume itsnatural form. The temporary set must of course be removed before thecold flow of the yarn produces a permanent set in its straight form. Formost yarns of the above type many months at least would be required forthis to take place so there 2,807,072 Patented Sept. 24, 1957 ice , 2 isno practical limitation as to the time between treating and weaving.

Examples of sizing agents which can be used are: Sodium polyacrylate,methyl cellulose, polyvinyl alcohol, cooked cornstarch.

As a specific example, nylon staple is spun into a suit able singlesyarn and is then ply twisted to a high ply twist in the same directionas the singles twist, or in the reverse direction depending upon theresult desired. A ply twist in the same direction usually produces aharder yarn which will coil more effectively in the final treating step.The yarn may then be skein dyed, the fibers may have been stock dyedprior to spinning, or the yarn may remain in undyed form prior toweaving, as desired.

The yarn in its high twist form is then permanenfly set by subjectingthe same to steam under pressure or by heating under conditions commonlyused for setting thermoplastic yarn.

The permanently set yarn is then reverse twisted to impart a final plytwist of the opposite hand of about onehalf the number of turns of theoriginal ply twist.

The reverse twisted yarn is then dipped in a 0.24% solution of sodiumpolyacrylate (dry solids basis). After immersion the yarn is dried understraightening tension at F. for one-half hour or under equivalent dryingconditions to leave a dry coating of the sodium polyacrylate on theyarn.

The yarn now remains straight and can be woven as cut pile on anAxminster loom or over pile wires on a velvet or Wilton loom or may befabricated into upholstery fabric, flat fabric, or a knitted fabricusing the usual fabricating techniques.

After fabrication the fabric is treated with wet steam at atmosphericpressure or with warm water to remove the coating and allow the yarn toassume a shape to relieve its internal strains. The reverse twisted yarnabove described coils into helical form with the plies separated andforming interleaved helices as shown in the Mersereau et al. patentabove mentioned. In the case of flat or knitted fabrics the yarn coilsto produce increased fullness and also contracts in a lengthwisedirection.

The same technique can be employed for other types of yarns which are tobe temporarily set. For example hard twisted frieze yarn which istwisted to a point where it tends to cockle when released can betemporarily straight set as above described, woven as pile, or otherwisefabricated into fabric and relaxed to assume its cockled form.

A typical pile fabric embodying this invention is shown in the drawingwherein the figure is a detail view of an Axminster pile fabric. Thepile fabric is shown as comprising a backing 10 and a plurality of piletufts 11 which are composed of multiply yarn with the plies 12 separatedand coiled into the form of interleaved helices.

Various other embodiments will be apparent to a person skilled in theart.

What is claimed is:

1. The method of making an Axminster pile fabric, which comprises hardtwisting a synthetic thermoplastic multiply spun yarn in one direction,heating said yarn to permanently set the same, reverse twisting saidyarn to impart a loose final reverse twist, applying to said yarn whileunder straightening tension a coating of a material having sufiicientstiffness to resist the internal forces produced by said reversetwisting, weaving an Axminster fabric employing said coated yarn as thepile yarn, and subjecting said fabric to a treatment for removing thecoating from said coated multiply yarn and causing the plies of the pileyarn to separate and coil into the form of interleaved helices.

2. The method of making an Axminster pile fabric, which comprises hardtwisting a synthetic thermoplastic multiply spun yarn in one direction,heating said yarn to permanently set the same, reverse twisting saidyarn to impart a loose final reverse twist, dipping said yarn in acoatingsolution of sodium polyacrylate, drying-saidyarnwhile the same isheld under straightening tension, weaving ani Axminster fabric employingsaid coated yard as the pile yarn, and subjecting said fabric to atreatment forrernoving the coating from said coated multiply yarn andcausing the plies of the pile yarn to separate and coil info the form ofinterleaved helices.

3. The method set forth in claim 1' in which said coating materialcomprises sodium polyacrylate.

4. The method set forth in claim 1 in which said coating materialcomprises methyl cellulose.

5. The method set forth in claim 1 in which said coating materialcomprises polyvinyl alcohol.

6. The method set forth in claim 1 in which said coating materialcomprises cooked cornstarch.

7. A fabric produced in accordance with the method set forth in claim 1.

References Cited in the file of this patent UNITED STATES PATENTS2,018,017 Fulton et al Oct. 22, 1935 2,089,947 Dickie et al Aug. 17,1937 2,089,948 Dickie et al. Aug. 17, 1937, 2,265,202 Schneider et a1.Dec. 9, 1941 2,401,828 Kahil June 11, 1946 2,662,588 Mersereau et a1Dec. 15, 1953 2,771,660 Ephland Nov. 27, 1956

